This invention relates to a timbre forming device for electric or electronic music instruments and, especially, to a device for freely forming timbre of electric string music instruments such as electric guitars.
For example, such an electronic music instrument as disclosed in the opened Japanese patent gazette No. S63-137295, which is referred to as "guitar synthesizer", is arranged to detect a pitch from a string vibration signal in a control unit and produce a musical sound from a sound source based upon the pitch. In such guitar synthesizer, it has been a general practice to attach a pickup in the vicinity of a bridge for improving separation of adjoining strings and satisfying pitch detection. However, the string vibration signal detected by the pickup located in such position includes a lot of higher harmonic components and, therefore, it must be passed through highpass filter, lowpass filter, bandpass filter and the like for timbre formation before it is used. However, it is impossible to obtain such a good musical sound signal as detected by a pickup attached at a general position, by such conventional filters only.
As another way, it has been proposed to attach pickups for guitar synthesizer, that is, so called divided pickups which respectively correspond to the strings and can individually detect vibrations of the respective strings, in the vicinity of the bridge of a conventional electric guitar so that the electric guitar can be used as a controller of the guitar synthesizer, and to use as a string vibration signal the output signal of the original pickup of the electric guitar. However, this system has such a disadvantage as high cost and confinement of pickup attaching position.
Accordingly, an abject of this invention is to provide a timbre forming device which can produce, from a string vibration signal with a lot of higher harmonic components detected by divided pickups attached in the vicinity of the bridge, a musical sound signal having a timbre similar to what is obtained from a string vibration signal detected by a pickup attached in a general position.
Another abject of this invention is to provide a timber forming device which can freely change the timbre of the above-mentioned musical sound signal.
When a pickup is fixed with respect to a string, its output level becomes nearly zero for a vibration having its node at the position of the pickup and maximum for a vibration having its loop thereat. More specifically, the output has a wave-like frequency characteristic determined by the pickup position and, therefore, the resultant musical sound signal has a timbre which is different from a natural musical sound and peculiar to the musical instrument.
Accordingly, a further object of this invention is to provide a frequency characteristic compensation device which can remove the above-mentioned frequency characteristic from the string vibration signal detected by the pickup to produce a string vibration signal akin to a natural sound.